Vehicle manufacturers have realized that it may be desirable under some conditions to automatically start and stop an engine of a vehicle. Stopping the engine can reduce fuel consumption, especially when the vehicle is stopped for longer periods of time, in stop-and-go traffic for example. However, continuously stopping and starting an engine can increase starter degradation, current consumption, engine noise and vibration, and starter one-way clutch degradation.
The inventors herein have recognized the above-mentioned disadvantages and have developed a method for improving engine starting.
One embodiment of the present description includes a method for starting an engine, comprising: stopping the engine; predicting a first combustion cycle of a cylinder from engine stop in which an air-fuel mixture is combusted; engaging a starter; and disengaging said starter during the predicted first combustion cycle.
Engine starting can be improved by disengaging a starter at a predetermined position that may be related to the first cylinder to combust an air-fuel mixture since an engine stop. For example, a starter can engage the flywheel of an engine while the engine is stopped. Upon engagement of the starter to the flywheel, the starter can begin to rotate the engine crankshaft and cause pistons within the cylinders to reciprocate. Crankshaft rotation causes valves that control flow through cylinders to operate, and valve operation and piston movement may be related such that they define or establish cycles of engine cylinders. And since cylinder cycles may be uniquely related to engine position, it may be possible to predict in which cylinder a first combustion cycle will take place. In particular, an engine controller can predict a first combustion event since engine stop in a cylinder based on engine position and cylinder fueling data. Therefore, it is possible to predict when the engine will start so that a starter may be disengaged early during an engine start.
The present description may provide several advantages. Specifically, the approach may reduce starter degradation, current consumption, overrunning clutch degradation, and engine noise/vibration. Further, the method may provide these benefits without additional hardware.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.